After 1942, many small subcamps were set up near factories to provide forced labor. IG Farben established a synthetic rubber plant in 1942 at Monowitz concentration camp (Auschwitz III); other camps were set up next to airplane factories, coal mines and rocket propellant plants. Conditions were brutal and prisoners were often sent to the gas chambers or killed on site if they did not work quickly enough.
At Auschwitz, there was a team of Nazi doctors who conducted experiments, but the two most notorious were Dr. Carl Clauberg and Dr. Josef Mengele. Dr. Clauberg focused his attention on finding ways to sterilize women, by such unorthodox methods as X-rays and injections of various substances into their uteruses. Dr. Mengele experimented on identical twins, hoping to find a secret to cloning what Nazis considered the perfect Aryan.
Nazi Germany maintained concentration camps (German: Konzentrationslager, KZ or KL) throughout the territories it controlled before and during the Second World War. The first Nazi camps were erected in Germany in March 1933 immediately after Hitler became Chancellor and his Nazi Party was given control of the police by Reich Interior Minister Wilhelm Frick and Prussian Acting Interior Minister Hermann Göring. Used to hold and torture political opponents and union organizers, the camps initially held around 45,000 prisoners. In 1933–1939, before the onset of war, most prisoners consisted of German Communists, Socialists, Social Democrats, Roma, Jehovah's Witnesses, homosexuals, and persons accused of 'asocial' or socially 'deviant' behavior by the Germans.